patterns

CQRS (Command Query Responsibility Segregation) pattern with separate command and query paths, domain event publishing, read model synchronization, and DTO transformation.

Full FlowZap Code

Client { # Client Application
n1: circle label:"Start"
n2: rectangle label:"User initiates action"
n3: diamond label:"Read or write?"
n4: rectangle label:"Send command"
n5: rectangle label:"Send query"
n6: rectangle label:"Receive response"
n7: circle label:"End"
n1.handle(right) -> n2.handle(left)
n2.handle(right) -> n3.handle(left)
n3.handle(right) -> n4.handle(left) [label="Write"]
n3.handle(bottom) -> n5.handle(top) [label="Read"]
n4.handle(bottom) -> CommandSide.n8.handle(top) [label="Command"]
n5.handle(bottom) -> QuerySide.n16.handle(top) [label="Query"]
n6.handle(right) -> n7.handle(left)
}
CommandSide { # Command Side
n8: rectangle label:"Validate command"
n9: diamond label:"Command valid?"
n10: rectangle label:"Execute domain logic"
n11: rectangle label:"Persist to write store"
n12: rectangle label:"Publish domain event"
n13: rectangle label:"Return validation error"
n8.handle(right) -> n9.handle(left)
n9.handle(right) -> n10.handle(left) [label="Yes"]
n9.handle(bottom) -> n13.handle(top) [label="No"]
n10.handle(right) -> n11.handle(left)
n11.handle(right) -> n12.handle(left)
n12.handle(bottom) -> EventHandler.n14.handle(top) [label="Event"]
n12.handle(top) -> Client.n6.handle(bottom) [label="Success"]
n13.handle(top) -> Client.n6.handle(bottom) [label="Error"]
}
EventHandler { # Event Handler
n14: rectangle label:"Receive domain event"
n15: rectangle label:"Update read model"
n14.handle(right) -> n15.handle(left)
n15.handle(top) -> QuerySide.n16.handle(bottom) [label="Sync"]
}
QuerySide { # Query Side
n16: rectangle label:"Parse query parameters"
n17: rectangle label:"Query read store"
n18: rectangle label:"Transform to DTO"
n19: rectangle label:"Return results"
n16.handle(right) -> n17.handle(left)
n17.handle(right) -> n18.handle(left)
n18.handle(right) -> n19.handle(left)
n19.handle(top) -> Client.n6.handle(bottom) [label="Data"]
}

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